Case Study: Successfully
Designing, Installing, and
Testing a Microgrid
Scott Manson,
Technology Director Schweitzer Engineering Laboratories, Inc.
• Microgrid projects
• Lessons learned
• Technology advancements
• Remaining challenges
Chronological History of Microgrids
• Multifunction protection
• Remote I/O
• Metering
• Power quality monitoring
• Programmable logic
controller
• IEC 61850
• Sequence of Events records
• High-speed
communications
• Continuous
self-diagnostics
• Synchrophasors
• DC battery monitoring
• Human interface displays
• Trip and close controls
• Oscillography recorder
1984–2004 Microgrid Intelligence Multifunction Microprocessor Relays
Evolve Rapidly
2002 – Motor Oil Hellas Korinthos, Greece
Centralized
Microgrid
ControlsFront-End
Processing
Relay Relay Relay Relay Relay
2,500
Relays
Utility
Loads
Front-End
Processing
• Front-end processing facilitates scaled
architecture and subcycle communications
• Crosspoint switch enables subcycle
load shedding
• Subcycle load shedding allows seamless
islanding
2002 – Motor Oil Hellas Speed Is Essential for Seamless Islanding!
2002 – Motor Oil Hellas Lessons Learned
Crosspoint Switch
Trigger
Inputs
Contingency Loads Selected to Shed
1 2 3 4 5 6
G1 Trip X X
G2 Trip X X
G3 Trip X X
G4 Trip X X X
Bus Tie Trip X X X
f
t CB Opens
Load-
Shedding
Outputs
Quantity of IEDs1 10 100 1,000 10,000
0
20
402002 2015
Closed Loop
Load-Shedding
Time (ms)
2006 – Saudi Aramco Shaybah, Saudi Arabia
Plant 3
(69 kV AIS)
Plant 2
(115 kV GIS)
Plant 2
(230 kV GIS)
Plant 1
(230 kV GIS)
2006 – Saudi Aramco Factory Acceptance Tests Improved With
Hardware-in-the-Loop Testing
Controller
Inputs
ControllerStatus
Controls
Dynamic
Simulation
System
Outputs
Generation Runback Making Turbine Respond at Speed of Inverter
MW
t
Contingency Detected (breaker trips)60 MW (actual load)
30 MW (runback target MW load)
Signal Sent by Generation-Shedding System
Maximum Runback MW Setpoint
Speed
Reference
Speed Feedback
Speed ControlValve
Control
Runback Reference
Runback
Selector
Valve
Dynamic Behavior Requires
Modeling Mechanical and
Electrical Systems
0.96
1.0
Power (pu)
Frequency (pu)
1.0
Steady-State
Droop Line
3
21
Transient Governor
Behavior
Governor
Frequency
Set Point
System Synchronization Safely Reconnecting Islanded Grids
Graphical Interfaces Teach Operators to Dispatch Grid Differently
Battery
CFE
(Mexico)
AEP
(U.S.A.)
Local Distribution
Inverter
Google®
2008 – Presidio, Texas 4 MW NaS Battery Microgrid Controls
Short-Term
Capacity Limit
Long-Term
Capacity Limit
Inverter-Based
Generation
Q
P
Q
P
Rotating
Generators
2008 – Presidio, Texas Inverters Are Not as Robust as
Rotating Machinery
Google®
2010 – BHP Worsley Alumina Collie, Australia
Electric Utility
STG-A STG-B STG-C STG-D
15 MW
STG-C Grid Island
55
54
53
52
51
50
49
48
47
Fre
qu
en
cy (
Hz)
Time (ms relative)
120,000 140,000 160,000 180,000 200,000 220,000
47
48
49
50
51
52
53
54
55
120000 140000 160000 180000 200000 220000
Fre
qu
en
cy (
Hz)
Time ( ms relative)
Steam turbine and boiler
control scheme changed
under islanded conditions
2010 – BHP Worsley Alumina Islanded Steam Turbines and Electronic
Loads May Not Mix!
Fre
qu
en
cy (
Hz)
47
48
49
50
51
52
53
54
55
0 50 100 150 200 250 300
Time (seconds)
10:17:35.701
Circuit Breaker
Open
10:18:43
Automatic
Synchronization Start
10:19:10.928
Underfrequency Level 1
Shed 0.93 MW
10:19:25
Oscillation
Start Governor
10:21:38
Isochronous Mode
10:21:46.929
Generator Trip
2010 – BHP Worsley Alumina Intentional Disconnecting at PCC
Increases Reliability
df/dt (Hz/s)
X1 X2
Y1
Y2
–X1–X2
–Y1
–Y2
Δf (Hz)
Trip
Region 1
Trip
Region 2
• Large system designs
were scaled down in
cost and complexity
• Early participation in
designs reduced costs
Protective
Relays
Local
Visualization
Engineering
Applications
Thin Clients
IO modules
Microgrid Controller
Layer 1 – Protection
Layer 2 – Controls
Layer 3 – Visualization
Layer 3.5 – DMZ
Physical Security Perimeter
Firewalls
Firewalls
Layer 3.5 – Business Networks
Firewalls
In-Depth Cybersecurity Is Required!
2012 – Chevron Jack
and St. Malo Offshore Platforms
Complexity Required to Be
Scaled Down for Remote Facility
• User inputs
System inertia
Load composition factors
• Live relay measurements
Loads and source metering (kW)
Frequency and df/dt triggers
Inertia Compensation and
Load Tracking (ICLT) Balances Power Mismatch for
Underfrequency Events!
98
0
97
96
95
94
93
92
91
Po
we
r (M
W)
5 10 15 20Time (seconds)
Electrical Power
Mechanical Power
Speed
Outside
Networks
Security GatewayVisualization, Economic
Optimization, Engineering Tools
Central Controllers
Communications Equipment
Current and
Voltage TransformersCircuit Breakers
Power Generation
Controllers
Protective
RelaysRemote I/O
Metering and
Power Quality
Layer 4
Layer 3
Layer 2
Layer 1
Layer 0
Tier 2 and 3
MGCS
Tier 1
MGCS
Microgrid
2014 – University of California
San Diego, California
Industrial and utility technology,
procedures, modeling, testing, and
commissioning methods were a perfect fit!
21 3 4 5
1.8 MW
12 kV
69 kV
Phase 2
CS CS
Relay Relay
Phase 3
RelayV RelayV
V
Relay
V
Relay
V
Relay
Phase 1
V
Relay
1.8 MW
Automation
Controller
G2
Relay
G1
Relay
Relay
500 kW
Battery
System
Relay
Phase 2
1 MW
Battery
System
Relay
2015 – Borrego Microgrid 2.0 PCC Is Protection Challenge
Protection
Meter and I/O
Protection
Meter and I/O
Tesla
Battery
Synchronous Condenser
and Flywheel
Protection
Meter and I/O
RTAC
Computer
HMI
HMISecurity
Gateway
WAN
Relay
Relay
Computer
Relay
Clamp-On
CTs for
Monitoring
Key Points
of Grid
Microgrid
Controls
Serial
Data
Diode
Portable Control Center
Utility PCC Diesel
GeneratorsWind TurbinesPhotovoltaic
Solar Cells
Monitoring
and
DispatchMonitoring
and
Dispatch
Communication
Three-Phase Power
CT and PT
Relay Relay
Relay
Portable Control Center Protection Panels in Portable Control Center
Synchronous
Condenser and Flywheel
Tesla Battery
2, 250 kW, 4 hour
RTAC
Computer
HMI
HMISecurity
Gateway
WAN
Computer
Microgrid
Controls
Serial
Data
Diode
2016 – Navy Seabees Microgrid Controls, Protection, and
Security Can Be Small and Portable
Modern Microgrids Automatically
Separate, Survive, and Synchronize
Islanded
Operation
Synchronization
Reintegration Reconfiguration
Separation
Grid-Tied
Operation
Questions?
References
[1] E. R. Hamilton, J. Undrill, P. S. Hamer, and S. Manson, “Considerations for Generation in an Islanded Operation,” proceedings of the 56th Annual Petroleum and Chemical Industry Conference, Anaheim, CA, September 2009.
[2] A. Al-Mulla, K. Garg, S. Manson, and A. El-Hamaky, “Case Study: A Dual-Primary Redundant Automatic
Decoupling System for a Critical Petrochemical Process,” proceedings of the 6th Annual Petroleum &
Chemical Industry Committee Europe Conference, Barcelona, Spain, May 2009.
[3] S. Manson, A. Upreti, and M. J. Thompson, “Case Study: Smart Automatic Synchronization in Islanded Power
Systems,” proceedings of the Power and Energy Automation Conference, Spokane, WA, March 2013.
[4] S. Manson, A. Khatib, M. Checksfield, and P. Duffield, “Case Study: Simultaneous Optimization of Electrical
Grid Stability and Steam Production,” proceedings of the 61st Annual Petroleum and Chemical Industry
Technical Conference, San Francisco, CA, September 2014.
[5] S. Manson, G. Zweigle, and V. Yedidi, “Case Study: An Adaptive Underfrequency Load-Shedding System,”
proceedings of the 60th Annual Petroleum and Chemical Industry Technical Conference, Chicago, IL,
September 2013.
[6] S. Manson, B. Kennedy, M. Checksfield, “Solving Turbine Governor Instability at Low Load Conditions,”
proceedings of the 62nd Annual Petroleum and Chemical Industry Technical Conference, Houston, TX,
October 2015.